Is Work done when there is constant velocity?

AI Thread Summary
When carrying a bag at constant velocity, the net force acting on the bag is zero, indicating no acceleration. Consequently, the work done on the bag horizontally is zero since there is no net force in that direction. However, work is done vertically to counteract gravity, as the bag must be held up against its weight. The force exerted to hold the bag is equal to its weight, and since there is vertical displacement, work is done in that direction. Therefore, while no work is done horizontally, work is indeed done vertically to maintain the bag's position.
ericka141
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Homework Statement


"You carry your 14.0 kg bag of textbooks horizontally 1.8 m above the ground, at constant velocity for a distance of 25 m. Ignore wind resistance. How much work do you do on the bag in the process?"

Homework Equations


W=Fd
F=ma


The Attempt at a Solution


If work equals force times distance, and force is equal to mass times acceleration, wouldn't the whole thing equal zero because of the constant velocity = no acceleration?
 
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ericka141 said:
If work equals force times distance, and force is equal to mass times acceleration, wouldn't the whole thing equal zero because of the constant velocity = no acceleration?
The net force on the bag is zero. But what force do you exert and what work does that force do?
 
ericka141 said:
...If work equals force times distance...

W=∫F.ds
use that along with what Doc Al suggested.
:wink:
 
So is there only work being done in the vertical direction, aka. the force is takes you to physically hold the bag up?
 
If there's displacement in that direction, yes. Work is proportional to displacement.
 

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